Constant velocity joint



Nov. 3, 1959 G. A. WAHLMARK CONSTANT VELOCITY' JOINT 4 Sheets-Sheet 1 Filed April 25, 195'? @M www Nov. 3, 1959 G. A. WAHLMARK 2,910,845

CONSTANT VELOCITY JOINT Filed April 25, 1957 4 Sheets-Sheet 2 INVENTOR.

Nov. 3, 1959 G. A. WAHLMARK CONSTANT VELOCITY JOINT 4 Sheets-Sheet 5 Filed April 25, 1957 d Y a B N2 @Y V4.. i f Af 4. r//f/l QM.

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Nov. 3, 1959 G. A. WAHLMARK 2,910,845

CONSTANT VELOCITY JOINT Filed April 25, 1957 4 Sheets-Sheet 4 INVENTOR.

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Patented Nov. El, i959 une CONSTANT VELOCITY JOINT Gunnar A. Wahlmark, Rockford, lill.

Application April 25, 1957, Serial No. 655,072

10 Claims. (Cl. 64-21) This invention relates to universal joints for connecting drive and driven members having angularly disposed axes. More particularly, the invention relates to universal joints embodying means for achieving constant velocity drive between the drive and driven members.

Until recently all commonly used universal joints were of the Cardan type embodying a spider having two pairs of trunnions formed at right angles with one pair piv- `otally connected to each of the shafts. lt is commonly known that such conventional universal joints do not transmit uniform velocity from the drive shaft to the driven shaft but instead provide two accelerations and decelerations of speed of the driven shaft for each rotaltion of the drive shaft. While the average speed of rotation of the driven shaft is equal to that of the drive cshaft, the periodic fluctuations in speed cause serious 'vibrational problems which increase drastically as the .angularity between the shafts is increased. For example, @the maximum speed variation with a conventional uni- `versal joint is approximately 3% at a 10 angularity beitween the shafts while at 30 angularity this variation fjumps to approximately 29%.

In recent years various types of constant velocity funiversal joints have been devised in order to achieve :a driven shaft speed which is at all times the same as the `drive shaft speed. Most such constant velocity joints lhave utilized the principle of maintaining drive engage` Jment between the shafts in a plane which is perpendicular tto the plane defined by the axes of the shafts and which bisects the angle between the shafts. This plane is re- Vferred to as the constant velocity plane. An example of a constant velocity joint of this type is embodied in .my copending application Serial No. 611,842, filed September 25, 1956.

The present invention is the result of an elfort to jprovide constant velocity drive between universally con nected shafts without the necessity of providing means .for maintaining the drive connection between the shafts in the constant velocity plane.

It is an object of the present invention to provide an improved constant Velocity universal joint.

Another object of the invention is to provide a constant 'velocity universal joint in which the drive connection between drive and driven members occurs in a plane perpendicular to the axis of one of the members.

A further object of the invention is to provide a constant velocity universal joint capable of accommodating substantial thrust between the drive and driven members.

Still another object of the invention is to provide a constant velocity universal joint in which friction is substantially reduced.

A still further object of the invention is to provide a constant velocity universal joint in which drive elements universally connecting the shafts are carried by one shaft and are maintained at a constant distance from the axis of the other shaft.

An additional object of the invention is to provide a constant velocity universal joint in which the drive between the universally connected members is provided through spherically surfaced drive elements, the centers of which are disposed in a plane perpendicular to the axis of one of the members.

Another object is to provide a constant. velocity universal joint v hich is free from backlash.

A further object is to provide a constant velocity universal joint utilizing three drive elements to equally distribute the driving force.

An important object is to provide a constant velocity universal joint capable of driving at extreme angle with low friction.

Other objects, features and advantages will be apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

Figure l is a perspective view of a schematically illustrated constant velocity joint according to the present invention;

Figure 2 is an end elevational view of the universal joint shown in Figure l;

Figure 3 is a sectional view taken along the line 3-3 of Figure 2;

Figure 4 is a longitudinal sectional view of another joint according to the present invention utilized in a swash plate hydraulic device;

Figure 5 is a fragmentary sectional view taken along line 5 5 of Figure 4, but showing the axes of the drive and driven members of the joint aligned;

Figure 6 is a longitudinal sectional View of a third form of constant velocity joint according to the present invention illustrated as used in connection with another swash plate hydraulic device; and

Figure 7 is a sectional view taken along line '7-7 of Figure 6, but showing the drive and driven members axially aligned.

The constant velocity universal joint of Figures 1-3 is more or less schematically illustrated and is generally designated by the reference numeral lll. The joint includes a drive member il and a driven member l2, a designation chosen for simplicity of explanation only inasmuch as the drive may just as readily take place from member il@ to member The drive member lll includes a shaft portion 14 which is provided at one end with three pivot journals or trunnions which rotatably and shiftably carry three drive elements ld. The pivot journals lli are xedly secured to the end of the shaft and are equiangularly spaced in a plane which is perpendicular to the shaft 14, so that the pivots collectively dene a drive spiden The drive elements le are spherically surfaced and are provided with diametrical bores i7 which slidably receive th pivots lf3 in close fitting relation.

As illustrated in Figures 2 and 3, the drive member ll is rotatable about an axis which is disposed at an acute angle with respect to the axis of rotation 19 of the driven member l2. The centers of the spherical drive members lo are designated by the reference numerals Ztl, and these centers deiine a plane, designated by the reference numeral 2l (Figure 3), which is perpendicular to the axis lil of the drive member. The point of intersection of the axis lli with the plane 2li delines the center of the spider and is designated by the reference numeral Z2.

rlfhe driven member l2 may be of any suitable construction and herein is shown in the form of a circular plate having a centrally disposed drive recess 24 which is formed of three equiangularly spaced radial drive channels 25. The sides of each of the drive channels are defined by a pair of parallel drive surfaces 26, whih in turn are parallel to the axis l@ of the driven member 12. The respective of surfaces 2d are equally spaced on opposite sides of the axis. rl`he outer ends of the channels 25 are defined by cylindrical surfaces 27 which are equally spaced from the axis The drive surfaces 26 are spaced so that they snugly but rotatably receive the drive elements le of the drive member 1l.

When the drive member ll is rotated about its axis l5, the driven member l? rotated,

a is correspondingly through the spider pivots l@ the drive elements ld, and. the drive surfaces 2d.

to centrifugal force gen erated during rotation, the drive elements if out` wardly against the cylindrical surfaces 27, so that the centers Ztl of the drive elements are always equidistant from the axis 19 of the driven member l2. lf the drive member lll is rotated at a constant angular velocity, then the driven member l2 will be correspondingly driven at exactly the same constant angular velocity. This is because the points of contact between the spherical surfaces of the drive elements i6 with the ilat drive surfaces 26 are always maintained equidistant from the axis il@ of the driven member regardless of the angularity between the axes i8 and 19.

Since the spherical drive elements 16 are maintained radially outwardly by centrifugal force, the center 22 of the spider must shift with respect to the axis l@ of the driven member as the joint is rotated. Jl/hen the joint utilizes three drive elements as illustrated in Figures l3, the center 23 of the spider must shift its position lil-'3 with respect to the axis l@ of the driven member for every 60 rotation of the drive member, and the center of the spider is always shifted away from the drive element whose center Zd is in the plane dehned by the axes M and. i9, or is closest to plane. ribis is illustrated in Figure 3 which shows the spider center 22 shifted downwardly with respect to the axis i9 or' the driven member', away from the upper spherical drive element 116 whose center 2id at this instant is in the plane delined by the axes l@ and Actually, the magnitude of spider center shift is very sligrt for practical drive angles but is emphasized in the gures for the sake of clarity. rThe spider center maires nree complete 360 shifts with respect to the driven member axis with each complete 366 rotation of the joint. This means that the axis lil must change its 'toularity very slightly with respect to the axis l@ as the j t rotates. However, since the shifting of the center is very slight, the change in angularity can be readily accommodated through flexing of the shaft ld, if a long shaft is utilized, or in slight angular play in the joint connecting the shaft Mil to its driving member (not shown).

The principles of the joint illustrated in Figures l-3 are applicable for constructing a universal joint for operation at all rotational velocities, from ver y low velocities just sumcient to produce the desired centrifugal force elect on the drive elements, up to extremely high rotational velocities in the neighborhood of 20,000 to 30,000 rpm. or even higher'.

If desired, the joint ot Figures can be simpliied even further for low speed applications by lixedly securing the spherical drive element le on the spider pivots le', orby eliminating the spider pivots and iixedly securing the drive elements at the end of the shaft ll and to each other. if the joint is constructed in this manner, it will operate in exactly the same way except that the drive element whose center is closest to or in the plane de termined by the axes of the joint will not bear against the outward end of its channel Z5, so that the point of contact between this drive element and the driven member will -beslightly closer to the axis El?. Thus, the rotational velocity of the driven member will not be absolutely constant, but since the center shift is so slight, the very smallaccelerations and decelerations of the driven member which theoretically result will be so small as to be negligible, particularly at joint angles of 30 or less. For all practical intents and purposes, the a ,OU @Omfuced in this manner can also be considered a constant velocity joint.

ln Figures 4 and 5 a constant velocity joint 30, constructed in accordance with the present invention, is embodied in a swash plate type hydraulic device generally designated by the reference numeral 3l. The swash plate device 3l is of fixed displacement and may be operated either as a pump or as a motor and includes a stationary casing having swash plate hydraulic mechanism 34 rotatably mounted therein. The mechanism 34 includes a d or swash plate assembly 3S, which is rotatably mounted in the casing on antifrirction roller bearings 36 and 37 and antifriction'ball thrust bearings 3S, and a driven or piston block assembly 39, which is rotatably mounted on antiriction ball bearings 40. The block assembly bears against an angularly disposed race plate which provides an end closure for the T he swash plate assembly 35 and the cylinder bloclf` a scmbly are connected for cocurrent rotation` by means of the constant velocity joint Sil, to be desc'ri in detail later, to cause reciprocation of a plurality of pistons d?, (one of which is shown). The pistons are universally secured to the swash plate assembly ,35 andthe piston heads reciprocate in cylinders id which communicate with hydraulic inlet and outlet ports (one shown) through piston ports The port i5 which is shown can be either the inlet port or the exhaust port, depending upon whether the hydraulic device 3l iS being operated as a motor or a pump. The contacting surfaces between the face plate all and the cylinder block 39 are referred to as face valve, which controls communication betwecn the various cylinder ports d6 and the inlet and exhaust ports in the'face plate las the cylinder block assembly rotates. i I

For providing a mechanical power input connection, or output connection (depending upon whether the hydraulic device is utilized as a pump or a motor), the swash plate assembly has internal splines d'7 for Aconnection with a drive or driven shaft (not shown). In ,Vorder t0 prevent leakage between the rotating svi/ash plate assembly 3 5 and the stationary casing 32 a rotating seal assembly of any suitable construction is provided. i

The constant velocity universal joint 3d includes a drive unit dit having at each end afdrive spider yhaving three radially disposed, equiangularly 'spaced pivot trunnions or journals Sil. It will be ,noted that the trunn nions at one end of the drive unit arerotated 60 relative to the trunnions at `the other Vend in order that the slight center shifting of each spider be exactly lSO" out or" phase to reduce or eliminate vibration during rotation oi the swash plate mechanism. v

On each of the trunnion pivots 5l) a driveelenientsor drive roller 5l is rotatably mounted, andeach of' the drive elements is formed with an annular segm ntal spherical surface 5?; centered en the axis of the r ective pivot trunnion. The rollers S1 at one endjof thezdrive unit i9 are disposed Vin an axiallydisposeddrive recess 5d formed wit i theswash plate assembly 3.5, and the rollers 5l at the other end of the drive unitare disev ed in an axially disposed drive recess ormedwithinthe cylinder block assembly i i In a manner similar to the drivevrecess 24,\ofthe Yembodiment of Figures l-3, the driverecesses 15,4V 5 are each provided with radiallydisposed channelsh ng respective pairs of parailel drive surfacese whichien* gage the segmental spherical surfacesSZ oi f ierollers. The outward end surfaces of the rollers areprdv ed with seftmental spherical surfaces 5.7 whichsenga'geuseg mental cylindrical surfaces 5S of equivalent diameter defining the ends or. each of the drive channels of the drive recesses 54 and 5S. `The segmental cylindrical surfaces 53 are equidistant from thefaxes vofthe swash plate assembly SSVand the cylinder block assembly A39, respectively, and tor convenience the cylindricals'urfaces flue are centered on the respective axes of the rotatable as` semblies 35 and 39. The trunnion pivots 50 end short of the cylindrical surfaces 5S to allow clearance for assembly and operation.

In order to properly locate the drive unit 49 of the constant velocity joint 30, and, in addition, `to provide a desired preload on the face valve, the stem of the drive unit has an axial bore 60 which is open toward the `cylinder block assembly 39 and contains a light compression spring 61 bottomed on the blind end of the bore. A shitable stud 62 is seated on the free end of the spring 61, adjacent the open end of the bore 60, and engages a spheiically or conically ground end 64 of a central post portion 65 `of a seat element 66. The opposite recessed end of the drive unit 49 engages a spherically or conically ground end surface 67 of a central post 68 of another seat member 69. The seat member 69 is lixedly secured at the inner end of the splines 47 within the socket block assembly 35.

The resilient force exerted by the spring 61 resiliently positions the drive unit 49 against the seat element 69, thus eliminating all end clearance and preventing any possibility of chatter during operation. The resilient force exerted against the cylinder block assembly 39 through the seat element 66 is resisted by the face plate 41 to provide a resilient preload in the face valve, -to control the pressure between the valve faces and to control leakage. The resilient preload on the face valve faces is very important and must be properly balanced since excessive spring force will result in excessive wear in the face valve while inadequate spring force will permit excessive leakage. The provision of the locating spring 61 also makes the unit easier to machine and to assemblesince otherwise close tolerances would be required to properly locate the drive unit 49.

The swash plate mechanism shown in Figures 4 and 5 operates in the manner described in detail in my copending applications Serial No. 583,797, tiled May 9, 1956, and Serial No. 611,842, led September 25, 1956, and thus the operation need not be described in detail here. The particular construction illustrated has a iixed swash plate tilt resulting in iixed displacement providing a capacity of eight gallons per minute at 24,000 r.p.rn.

ln the device illustrated in Figures 4 and 5 the constant velocity universal joint does not carry full Itorque between the swash plate assembly and the cylinder block assembly 39 but is provided to coordinate rotation of these two assemblies against vfrictional forces, or, in other words, -to properly time the rotation. When the mechanism is rotated at operational speed, centrifugal force keeps the drive rollers 51 out against the segmental cylindrical surfaces 58, so that the centers of the segmental spherical surfaces 52 are maintained equidistant from the respective axes of the swash plate assembly 35 and the cylinder block assembly 39. Consequently, the points of engagement with the drive surfaces 56 are always equidistant from the rotational axes and absolutely constant velocity drive is achieved between the two lassemblies. Inasmuch as the constant velocity joint 30 is double ended (i.e. is provided with drive rollers at both ends), there is no need to provide for shaft flexibility or limited angular play as was the case with the embodi-` ment of Figures l-3. The very slight shifting of the centers of the two spiders of the drive unit 49, results in a weaving of the drive unit, but this slight weaving has no adverse effect on the operation of the joint, even at the extremely high rotational speeds involved.

The spring 61 and its associated elements resiliently position the spider to prevent chattering or displacement and at the same time to provide an `advantageous resilient preload between Ithe engaging -faces of the face valve. In the particular embodiment illustrated the spring 61 is designed to exert a force between 5 and 10 pounds. Of course, the force exerted varies for different designs but is always of relatively low magnitude.

6 In Figures 6 and 7 a third embodiment of constant velocity universal joint according to the present invention is shown utilized in a swash plate hydraulic device, generally designated bythe reference numeral S0. The joint of this embodiment is designated by the reference numeral 81.

The swash plate hydraulic device includes a. casing 82 housing variable displacement swash plate hydraulic mechanism 84, which can be utilized as a hydraulic pump ora hydraulic motor. The hydraulic mechanism 84 includes a tiltable swash plate assembly 85 and a cylinder block assembly 86. A plurality of pistons 87 (one shown) are universally secured to the swash plate assembly and have piston head portions reciprocably disposed in piston cylinders 88 formed in the cylinder block assembly. The cylinder block assembly is rotatably mounted in the casing by means of an antifriction ball bearing assembly 89. The swash plate lassembly 85 includes an outer control or tilt ring 90 which is pivotally mounted on a pair of trunnions 91 Which are rotatably secured t0 the casing 82 through antifriction ball bearings 92. A piston socket ring94 is rotatably mounted within the tilt ring 90 by means of antifriction roller bearings 95 and 96 and antifriction ball thrust bearings 97. The ends of the pistons 87 opposite .the heads are universally secured to the socket ring 94.

Mechanical power output or input is achieved through an internal shaft 98 having internal splines 99 at one end for receiving mating splines on a connecting shaft (not shown). A suitable rotating seal assembly 100 is provided at the juncture between the end of the internal Ishaft 98 and the casing.

Flow of hydraulic fluid to or from the cylinders 88 is accomplished through cylinder ports 101 which connect with hydraulic pressure and exhaust ports 102 (one of which is shown) formed in a stationary face plate 103. A wear plate 104 is secured to the face platel 103, and the abutting surfaces of the cylinder block assembly 86 and the wear plate 104 provide a face valve.

For controlling the tilt of the swash plate assembly 8S, suitable control mechanism 105 is provided, including a pair of control rods 106 which engage .the tilt ring 90 to change the angle of `tilt of the swash plate assembly and consequently the capacity of the hydraulic mechanism. j The constant velocity universal joint 81 provides a driving connection between the socket ring 94 and the internal shaft 98. The joint includes a hollow drive unit 107 having internal splines 108 which. are engaged by external splines 109 formed at the inner end of the internal shaft 98. The splines are constructed so that there is no rotational play, but a slight amount of angular play is permitted to accommodate slight shifting of the axis of the drive unit during rotation of the joint.

At its other end the drive unit 107 includes three pivot trunnions or journals 110, which are. radially disposed and equiangularly spaced in the manner described in connection with the pivots of the previous embodiments, providing a drive spider. A drive member 111 is rotatably disposed on each of the pivots 110 by means of antifriction ball bearings 112. The drive elements 111 are provided with segmental spherical surfaces 114 which are disposed in close fitting relation between respective pairs of parallel drive surfaces 115 delining three short, radially extending, equiangularly spaced drive channels of a drive recess 116 axially formed within the socket ring 94. The spherical surfaces 114 are centered on the axes of the respective trunnions 110.

The opposite end of the drive unit 107 is provided with a radial flange 1'17 having external splines 118 engaging mating internal splines 119 formed within the cylinder block assembly 86 adjacent the antifriction bearing '89.

Means are provided for resiliently locating the spider 107 while at the same time maintaining a desired preload on the face valve. For this purpose a coil compression spring 120 is disposed in an axial bore 121 formed in the` inner end portion of the internal shaft 98. The spring 120. is bottomed at the blind end of the bore and resiliently bears at its other end. against a spring lseat member 12,2, which is secured within the inner end ofthe drive unit 10.7 by. means of a snap ring 124. The internal shaft 98 is provided with an annular flange 125 which bears against the end of'a plain bearing 12.6 secured within the end of the housing 82, so that the'spring 120 resiliently urges the drive unit 1051'. towardthe left, as illustrated in Figure. 6, tov position the flange 117 against the outer race of the antifriction bearing 89. rihe bearing, in turn, urges the cylinder block assembly against the Wear plate 104 ofv the face valve tok produce the desired resilient preload on the face valve. I

When thev hydraulic mechanism is utilized as a pump, the socket ring 94 and the cylinder blockassembly '86 are rotated causing reciprocation of the pistons to pump hydraulic liquid in accordance with the speed of rotation and the angle of tilt of the swash plate assembly. lIf the device is being utilized as a motor', liquid under pressure is selectively introduced into the piston cylinders ahead of the piston heads to cause reciprocation' of the pistons and to thereby cause rotation of the swash plate assembly, so. that the internal shaft 98 is rotatedl through the joint 81. For a more detailed explanation of the operation of hydraulic mechanism of this type, reference is made to my prior copendingy applicationsv Serial No. 583,797, filed May 9, 1956, and Serial No. 611,842, filed September 25, 1956.

The constant velocity joint 81 operates in much, the same manner as the joints of the previous embodiments except that the drive elements 11.1' are not moved outwardly by centrifugal force inasmuch as they are retained in their rotatable position by the antfric'tion bearings 112. Thus, as the hydraulic mechanism. operates with the swash. plate assembly tilted, the center offthe spider of the drive unit shifts slightly and carries with itk the drive elements 111. This produces a very slight shifting of the points of contact of the drive elements with the drive surfaces during rotation of the joint, s o that, theoretically at least, slight fluctuations in velocity occur between the spider and the socket ring 94. However, the theoretical fluctuations in velocity are so slight that they have no adverse effect, and for all practicalv purposes thejoint transmits true constant velocity, particularly when the segmental spherical surfaces 114l are of relatively. large diameter as illustrated in Figures 6 ande 7, l The very slight Weaving of the axis ofthe spider '107A is accommodated' in the slight angularplay permitted-between the splines 108 and 10.9.. Actual constructioniand" operation of a device such as shown in this embodiment has eifectively, illustrated that theV theoretical velocity variations are, in fact negligible, so that the joint transmits constant velocity from a practical standpoint. Becauseof the arrangement of the parts in the embodiments of Figures 6 and 7, the constant velocity jointVSl carries full torque.

In all of the embodiments described it is advantageous to use three driving elements as described, because 'the three elements find their own centers under load and thus the driving effort is evenly distributed between the three regardless of minor errors in indexing andmaehining. However, it will be understood that a larg?? number can b e used, `if desired, as long as the partsfare accurately constructed. lt. is also possible to use only two driving elements but in doing so means illust bt?. provided to assist in stabilizing and centering theY drive unit spider.

The joints ofl this invention are practically. free from backlash because the drive elements .can be ttedl in the drive channels with practically. no. clearance due to the fact that thel drive effort is achieved through rolling contact. The provision of parallel dat. surfaces in the drive channels makes4 for easy` machining, andthe spherical surfaces ofthe drive elements readilyY rollon the flat: drive surfaces. The joints are` particularlyA well adapted fory high speed operation, and they can be used for extreme drive angles. with low friction.

It will be readily understood that the constant velocity universal joints of the present invention can be utilized in any type of mechanical device, requiring angular drive. However, theyn Vare particularly well adapted for use in swash plate hydraulic devices.

Variations and modifications may be effected without departing from the scope of the novel concepts of the present invention.

l claim:

l. A constant velocity universal joint comprising a drive member, a driven member, a plurality of drive elements secured to one of said members deiining a plane perpendicular to the axis of said `one member, a plurality of drive channels formed in the other` of" said members, each ofv said channels having a pair of parallel surfaces engaging the respective drive elementson opposite sides thereof, means for maintaining said drive elements equidistant from the axis of said other member'when said joint is rotated, and means accommodating weaving ofy the axis of said one member relative to the axis of the other member when said joint is rotating with the axes of the members angularly disposed.

2. A constantvelocity universal joint comprising a drive member, a driven member, a plurality of drive elements secured to oneof said members, drive surfaces on the other of said members in driving engagement with said drive elements, means for maintaining said drive elements equidistant from the axis of said other member when said joint is rotated, and means accommodating weaving of the axis of said one'member relative to Ithe axis ofthe other member when said joint is rotating with the axes of the members angularly disposed.

3. A constant velocity universaljoint according to claim 2 wherein said drive elements are three in number.

4. A constant veloci-ty universal joint comprising a drive member, a driven member, a plural-ity of drive elements securedy to one of saidy members for'rotation about and shifting along axes which are equiang'ularly'spaced and intersect the axis of said one member at a Vgiven point, said drive elements having spherical surfaces about their axes of rotation, a plurality of parallel pairs of drive surfaces forrned on the other of said members parallel to the axis of said other member, the drive surfaces offeach pair engaging the spherical surfaces of; the respective drive elements in close fitting relation on opposite sides of each drive element, meansA on said` other member for restraining youtward shifting ofl said drive elements under influence of centrifugal force to maintain the drive elements equidistant from the axis'of rotation vof said other member.,A and Vmeansr accommodating shifting of said given point relative to the axis of said other member when said joint is rotated, with the axes of the. members angularly disposed. i

' SfA constant velocity universal joint comprisinga drive member, a driven member, a plurality of drive rollers rotatably and axially shiftably secured to one of, said members, said drive rollers having annular sphericalsurfaces with their centers on the axes of rotationy o f the rollers',` the axes` of rotation of the roller-sy being, perpendicular to and engaging `the axis of said one member at a given point, and a drive recessA formedy in the other of said members including plurality of drive channels equiangularly spaced about the axis of said other mem-` ber andr having side surfacesy in close fittingV engagement with the spherical surfaces on said drive rollers, said channels having end stop surfaces equidistant from the axis of saidfother member, said stop surfaces being spaced radially outwardly from lthe' adjacent portions of said one member, and saidY rollers having segmental spherical end Surfaces adaptedfor engaging Vthe stop surfaces of saidl channels, whereby saidrollers areV urged radially outwardly under the inuence ofc'entrifuga'l force so that said -spherical end surfaces engage said stop surfaces to maintain the centers of said annular spherical surfaces equidistant from the axis of said other member, and whereby the spacing between said stop surfaces and said one member accommodates weaving of the axis of said one member relative to the axis of said other member when said joint is rotated with the axes of the members angularly disposed.

6. A constant velocity universal joint comprising a drive member, a driven member, a drive unit disposed between said members, a spider secured at each end of said drive unit, each of said spiders having a plurality of trunnions with axes equiangularly disposed in a plane perpendicular to said drive unit, a spherieally surfaced drive element rotatably mounted on each of the respective trunnions, an axial drive recess formed in each of said members, each of said drive recesses havingA a plurality of pairs of parallel drive surfaces disposed parallel to the axes of the respective trunnions and to the axes of the respective members and engaging the spherical surfaces on the respective drive elements in close litting relation, and means for maintaining the respective drive elements equidistant from the axes of the respective members, the outward ends of said trunnions being spaced from adjacent portions of said members to accommodate weaving of the drive unit relative to said members when said joint is rotated with the axes of the members angularly disposed.

7. A constant velocity universal joint according to claim 6 wherein each of said spiders has three trunnions,

8. A constant velocity universal joint comprising a drive member, a driven member, a drive unit disposed between said members, a plurality of drive rollers rotatably and axially shiftably secured at each end of said drive unit on axes which are equiangularly spaced and intersect the axis of said drive unit at respective points, said drive rollers having annular segmental spherical surfaces about their axes of rotation and segmental spherical end surfaces, and a drive recess formed in each of said members, each of said drive recesses including a plurality of drive channels equiangularly spaced about the axes of the respective members and having side surfaces in close fitting engagement with the annular spherical surfaces on said drive rollers, said channels having end stop surfaces equidistant from the axes of the respective members and spaced outwardly from adjacent portions of said drive unit, whereby said rollers are movable radially outwardly under the inuence of centrifugal force to engage said spherical end surfaces against said stop surfaces to maintain the centers of said annular spherical surfaces equidistant from the axes of the respective members and whereby the outward spacing of said stop surfaces accommodates weaving of said drive unit relative to said members when said joint is rotated with the axes of the members angularly disposed.

9. A constant velocity universal joint comprising a drive member, a driven member, a drive unit disposed between said members, means drivingly connecting said drive unit with one of said members, a plurality of drive elements secured to said drive unit, said drive elements having spherical surfaces Ithe centers of which are disposed in a plane perpendicular to the axis of said drive unit, a drive recess axially formed in the other of said members and having a plurality of radially extending channels receivingsaid drive elements in close tting relation with said spherical surfaces, a first positive stop engaging one end of said drive unit, said drive unit having a blind axial bore open at the other end thereof, a compression spring disposed in said bore and bottomed on the blind end thereof, a shiftable stud seated on the other end of said spring, and a second positive stop engaging said shiftable stud, whereby said spring resiliently positions said drive unit against said rst positive stop.

10. A constant velocity universal joint according to claim 6 wherein the trunnions of one of said spiders are eguiangularly spaced with respect to the respective trunnrons of the other of said spiders.

References Cited in the file of this patent UNITED STATES PATENTS 2,125,615 Kittredge Aug. 2, 1938 2,155,455 Thoma Apr. 25, 1939 2,532,433 Wingquist Dec. 5, 1950 2,691,876 Wildhaber Oct. 9, 1954 'rf-"-fn-f-rT---r 7! 

